In recent years, individual recognition technology has attracted attention. For example, there is a technology to be used for production and management, in which information such as a history of the object is clarified by giving an ID (an individual recognition code) to an individual object. Above all, the developments of semiconductor devices that can send and receive data without contact have been advanced. As such semiconductor devices, in particular, a wireless chip (also referred to as an ID tag, an IC tag, and IC chip, an RF (Radio Frequency) tag, a wireless tag, an electronic tag, or an RFID (Radio Frequency Identification)) is beginning to be introduced into companies, markets, and the like.
Many of semiconductor devices that have already been put to practical use each have a circuit using a semiconductor substrate such as a Si substrate (also referred to as an IC (Integrated Circuit) chip) and an antenna, and the IC chip includes a memory circuit (also referred to as a memory) and a control circuit. By particularly equipping a memory circuit which can store much data, a high-value-added semiconductor device providing higher performance can be provided. Further, such semiconductor devices are required to be manufactured at low cost. In recent years, organic TFTs or organic memories using organic compounds for the control circuits and memory circuits have been actively developed (Reference 1: Japanese Patent Laid-Open No. 2004-47791).
As a general memory circuit provided in a semiconductor device, a DRAM (Dynamic Random Access Memory), an SRAM (Static Random Access Memory), an FeRAM (Ferroelectric Random Access Memory), a mask ROM (Read Only Memory), an EPROM (Electrically Programmable Read Only Memory), an EEPROM (Electrically Erasable and Programmable Read Only Memory), a flash memory, and the like can be used. Among them, in the case of a DRAM and an SRAM which are volatile memory circuits, data is erased when the power is turned off so that data is required to be written every time the power is turned on. An FeRAM is a nonvolatile memory circuit which uses a capacitor including a ferroelectric layer and requires a large number of manufacturing process. A mask ROM has a simple structure, however, data is required to be written during the manufacturing steps, and thus data cannot be additionally written. An EPROM, an EEPROM, and a flash memory are non-volatile memory circuits using an element having two gate electrodes, so that the manufacturing steps are increased.
On the other hand, as for a memory circuit using an organic compound, a memory element portion is formed by providing an organic compound between a pair of electrodes, in the case where a thick organic compound layer is formed, current hardly flows and the drive voltage is increased. When a thin organic compound layer is formed instead, the memory circuit is physically damaged easier due to short between electrodes or stress application; consequently, the reliability of the semiconductor device would be reduced.